What is the longest wavelength of light that is useful for p

What is the longest wavelength of light that is useful for photosynthesis? Why?

720

550

420

700

Solution

plant pigment molecules absorb only light in the wave length range from of 700 to 400nm, this range is reffred as photosynthetically active radiation. plants can use two common wave length for photosynthesis. these two are red and violet blue. red and yellow wave length light is longer, lower energy light while blue light is higher energy. in the spectrun of light the areas that drives the photosynthesis is highest is the red end (600-700nm), followed by blue region (400-500). answer is 700 considered approprite. (note :but 720 is partly considered accroding to some literature ( not sure)